US AZ vaccine trial

What does the recent US trial of the AstraZeneca Covid vaccine tell us?
30 March 2021

Interview with 

Jeremy Rossman, University of Kent


Healthcare worker drawing up influenza (flu) vaccine shot


This week, as Covid-19 cases continue to fall in the UK, they're surging in Europe, partly as a result of the spread of the Kent variant that's becoming the dominant circulating strain of the virus in many EU countries; the other factor is low levels of coronavirus vaccination achieved so far across the EU bloc. Some of that stems from skepticism in EU countries about the effectiveness of the AstraZeneca vaccine, so maybe that will change now thanks to the announcement of another successful trial of the vaccine, this time in the US. AstraZeneca have slightly revised their numbers since they made the trial results public, but they're still very encouraging. Chris Smith spoke to University of Kent virologist Jeremy Rossman to hear his reaction but asked him first whether, a year on from the UK first entering a lockdown, he expected us to be in the situation we are today...

Jeremy - Absolutely not. There's a lot that we had an idea of what was coming, in terms of the severity and the need for strong action. But the fact that we are still experiencing lockdowns, that we've spent a large portion of the year in lockdown, in dramatic restrictions, and that we still do not have a solid plan of how we are going to get out of this, is really beyond belief to me.

Chris - What did you think would happen? This time last year when we watched Boris Johnson deliver that press conference, when everyone was just glued to the TV and we all felt a shiver go down our spines, where did you think it would end? And when?

Jeremy - I wasn't sure. What I was hoping was that we would have a lockdown and that that would drive cases down. Now that absolutely did happen. But what I had been waiting for that didn't happen, was that we would use that period of time to build and reinforce the infrastructure needed when we got out of the lockdown. So that robust and functional test, trace, isolate support system. And then coming out of the lockdown, really gradually ease until we were sure the infrastructure was working to identify cases and outbreaks,, and then have a low level of cases. That was what I was hoping for. I was fearing that we would come out too fast and the infrastructure wouldn't be in place, and that cases would go up. But I did not expect to have so little functional infrastructure in place, for cases to go up so high, and then to go into another lockdown.

Chris - Do you think we're ready now?

Jeremy - No, unfortunately. I wish I could tell you something different, but right now I am extraordinarily worried that we are facing exactly the same situation that we faced several times over this past year, that we're going to ease lockdown and that cases are going to start to rise. We still don't have really good infrastructure. And the reliance right now is on the vaccines.

Chris - We got a bit more information this week though, about one of those vaccines, that was AstraZeneca's vaccine, which was a trial from the US, so what do we get from that trial in America? What can we take away from it that we couldn't have known already?

Jeremy - I think that there are three very important takeaways from this. The first is that AstraZeneca is still a very good vaccine, 79% efficacy at preventing symptomatic COVID, and then a hundred percent efficacy at preventing severe COVID hospitalisations and fatalities. The second thing is that this clinical trial included a significant number of people that were over the age of 65, because we wanted to make sure that we got good, robust data, that in fact, this vaccine does work well in the elderly. The final takeaway is that there's a real tendency to look at numbers and say, Oh, this is 79% efficacious. And this vaccine is 94% efficacious. And so this vaccine is better. And the issue is that you can't directly compare those numbers between different clinical trials, because they were done in different times. They were done with different dosing strategies, they were done in different populations. So what we need to conclude from this, is to say, look, we have more good data saying that this is a very good vaccine, but to not get too hung up on absolute numbers between the different clinical trials.

Chris - How'd you think this has gone down with the EU? Who, many EU countries have not been enthusiastic about this vaccine? In fact, some would say they've even gone as far as to trash it reputationally, what should they take away from this?

Jeremy - My hope is that what they will take away from this, is that they have added very solid and very good data that in fact, this vaccine does work very well, is quite safe. And in fact is very effective in the over 65 age group. And that specifically has been one point that has been really highlighted by EU countries as a real concern about the vaccine. And unfortunately, it's been phrased in very poor ways, saying that it doesn't work in that age group when in fact really, they just didn't have the data to say that it worked. So now we have the data. So my hope is that this will help convince people in the EU that in fact, this is a good vaccine.


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